The U.S. Justice Department said on Friday that its investigation into the handling of rape reports by prosecutors in Missoula, Montana, has found substantial evidence that the county attorney's office discriminates against women.

The 20-page letter caps a nearly two-year inquiry into how the Missoula County Attorney's Office deals with sexual assault. It was made public days after County Attorney Fred Van Valkenburg sued the U.S. Justice Department, accusing its attorneys of overstepping their bounds by trying to oversee local prosecutors.